Interpretive Summary: Modern poultry growers are familiar with Confined Animal Feeding Operation (CAFO) regulations put in place to reduce nutrient impacts on state waters, but may be less aware of how negative impacts on those waters are defined. In actuality, limits for nutrient concentrations in waters are being developed as Total Maximum Daily Loads (TMDLs). It would seem that there is some discontinuity between requiring CAFOs to limit nutrient discharges without knowing first what levels of nutrients are excessive. The simplest justification is that lawsuits have driven the U.S. Environmental Protection Agency to require permit reductions before adequate data has been collected to formulate nutrient standards. The following discussion provides an update on nutrient water quality standards in Mississippi and the development of TMDLs for the perspective of broiler growers.

Technical Abstract:
Confined Animal Feeding Operations (CAFOs) are regulated to reduce nutrient discharges to local waters, although nutrient water quality standards do not yet exist. At first, it may seem that there is some discontinuity between requiring CAFOs to limit nutrient discharges without knowing what levels of nutrients are excessive. The simplest justification is that lawsuits have driven the U.S. Environmental Protection Agency (EPA) to require permit reductions before adequate data has been collected to formulate nutrient standards. In many cases, farmers have been proactive in reducing impacts to local waters by using nutrient management plans. Unfortunately, the extent of their effectiveness is unknown. The Mississippi Department of Environmental Quality (MDEQ) is proposing nutrient attainment levels for state waters as Total Maximum Daily Loads (TMDLs) for total phosphorus (P), total nitrogen (N), chlorophyll, and turbidity. These four parameters are mandated by EPA. The MDEQ Nutrient Management Task Force held a milestone meeting on September 6, 2006 to discuss completion of monitoring and data collection for lakes and reservoirs, wadeable streams and rivers, and coastal estuaries which enabled the transition to data analysis and criteria development for these water body types. The MDEQ goal is to publish nutrient standards in 2008. Nutrient TMDLs remain a somewhat distant issue for the agricultural community at present, but as water quality standards are developed in the coming years, they may become the driver for new technologies and practices needed to further reduce nutrient inputs to the state's waters.